1. Field of the Invention
The present invention relates to a light source assembly employing light emitting diode, and more particularly to a light emitting diode based light source assembly having a heat sink for effectively dissipating heat.
2. Description of Related Art
Light emitting diode (LED) has many advantages, such as high luminance brightness, low power consumption, good matching with integrated circuit, long-term reliability and environment friendliness so that the LED has been widely used as backlight source in liquid crystal display (LCD) as described in an article entitled “Unique White LED Packaging Systems” cited in a publication of 2003 IEEE Electronic Components and Technology Conference written by Atsushi Okuno.
An LED device generally comprises a plurality of LEDs arranged side-by-side in a large density and generates a lot of heat in operation so that temperature of the LEDs gets very high. It is well known that the LED is a semiconductor device which is sensitive to temperature. Generally speaking, high temperature results in greatly reducing service life of the LEDs. Furthermore, high temperature also has a reducing effect on resistance of the LEDs so that electrical current through the LEDs becomes larger and more heat is generated and accumulates in the LEDs. Thus, a working condition for the LED device becomes worse and worse.
In a related art disclosed in U.S. Pat. No. 6,428,189 B1, an LED light source assembly includes a plurality of LEDs and a heat dissipater used to absorb heat accumulated in the LEDs. The LEDs electrically connect with a circuit board, and further extend through the circuit board to thermally contact the heat dissipater via a thermal coupling agent. However, the thermal coupling agent can not make a firm connection between the LEDs and the heat dissipater so that transferring heat between the LEDs and the heat dissipater becomes difficult. Thus, heat dissipating efficiency of the LED light source assembly is in a low level.
Accordingly, what is needed, therefore, is an LED light source assembly which has an improved heat dissipation efficiency.